﻿<p>The <em>IfcControlExtension</em> schema in the core layer declares basic classes for control objects (<em>IfcControl</em>, <em>IfcPerformanceHistory</em>) and assignment of these (<em>IfcRelAssignsToControl</em>) to any object derived from <em>IfcObjectDefinition</em>. Also, it declares the classes to associate resource level objects of controlling nature to any subtype of <em>IfcRoot</em>, using <em>IfcRelAssociatesConstraint</em> and  <em>IfcRelAssociatesApproval</em>.</p>

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HISTORY&nbsp; New schema in IFC2.0.
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